314 KEPOKT— 1891. 



rainfalls in various other districts of limited area, particularly 

 in the Provinces of Nelson and Wellington, and on the east 

 coast of Southland. The conclusion is inevitable. Rainfall 

 and forest must, as a general rule, be related to one another as 

 cause and effect ; and, though the two may have reacted on 

 one another to a limited extent, yet for the most part the rain- 

 fall has brought about the forest, rather than the reverse. 



Mountain-ranges as a rule are, as is well known, better 

 covered with forests than level country'. I do not think this 

 arises, as Darwin supposed, because plains are in themselves 

 less favourable to the development of arboreous growth than 

 broken and hilly country ; for some of the most extensive and 

 dense forests in the world extend over areas level as a table. 

 Mountain slopes and summits — particularly if at all formidable 

 — are little interfered with by man or cattle, and there growth 

 goes on more or less comparatively undisturbed ; and, as good 

 drainage and various aspects and different kinds of soil in 

 such situations are sure to be found, there various forms of 

 vegetable life, suitable to the climate, through the instru- 

 mentality of birds and winds spring into existence. But the 

 main cause why woods thrive on mountains better than on 

 plains is that rainfall increases, within certain limits, 3 or 4 

 per cent, for every 100ft. of elevation. 



Captain Walker, as if arguing desperately against his own 

 convictions, asks, if forests follow rainfall, " Why should not 

 rain have fallen and forests been created on the eastern slopes 

 of the mountains on which the clouds laden wdth moisture from 

 the Pacific first impinge? " The answer is conveyed in the 

 question. Eain has not fallen on the eastern slopes of our 

 Alps, because in this latitude the rain-bringing winds are 

 western, and comparatively little rain comes from the east 

 at all. The rain from the west has been intercepted by the 

 mountains, and, as there has been little rain, forests have not 

 been called into existence on the eastern slopes, except in a 

 few places where low passes have permitted the moisture to 

 cross to the leeward side. 



That woods do undoubtedly tend to the equalisation of 

 temperature, screen the soil from the sun, check evaporation 

 (which in open country is five times as great as in woods) 

 particularly from pools and streams, render the air about them 

 to some extent cooler and moister than it would be otherwise 

 through the immense surface that the leaves expose to radia- 

 tion and copious evaporation, and mechanically bind the soil 

 and check the lamning-off of moisture from its surface — all 

 this, in addition to then' grace and beauty of form and colour, 

 — for 1 share all Lord Beaconsfield's enthusiasm about trees, — ■ 

 nmst be granted. I will even go further and say that, in con- 

 sequence of some of the effects herein just enumerated, there 



